Electronic circuit designers must constantly address the issue of interference such as radio frequency interference (RFI) and electromagnetic interference (EMI) which affect the performance of the circuits which they design. Typical solutions to interference problems include separating circuits from one another in order to minimize interference, placing metal "cans" over sensitive circuits or circuits which are the generators of interference signals (e.g., oscillator circuits, etc.). Another problem presented when designing electronic circuits such as radio circuits is minimizing the amount of board space required to implement a given circuit. Furthermore, in the case of some circuits such as filters and transmitter circuits, it is also important to design circuits which can be tuned or adjusted in order to overcome the changes in circuits due to component tolerance variations, etc.
Cost is also a consideration. An inductor which is built into the same printed circuit board as the rest of the circuitry reduces material does not add much additional cost to the manufacturing cost of the electronic assembly. Another issue confronted by designers is component tolerances. Inductor make tolerance is a factor which influences circuit design and sometimes leads to high cost, tight tolerance inductors. A printed circuit board inductor of the type described in the present invention can be constructed inexpensively into a printed circuit board, using dimensions and spacing that conform to the circuit board manufacturers process limitations and hold tighter make tolerances than their discrete counterparts. Furthermore, there is a need in the art for an inductor which can be tunable and which can provide for improved shielding against interference.